New to welding Aluminum

[captain butch]

I was on earlier about MIG machines and you all warned me against buying a cheap machine. I did it anyway, a Chicargo Electric 151, 230v. I had a certified aircraft welder try to weld 3/16 stock using pure Argon sheilding gas, a total flop. He could weld with it but not very well. O.K. I'm convinced, I have a chance to buy a Lincoln 175 new for $458.00 Do you think this will answer the need for welding light weight 3/16 to 1/4 stock. My welder friend is long gone so I thought I'd seek your advice.

 

[Wynand N]

The gas is okay.
From experience I have found that helium gas works better with aluminuim than argonshield.
See that your machine OCV (open curcuit voltage) is on par or higher than the requirement of the CO2 welding wire manufacture spec. Also check the polarity.

It is advisable to have a push / pull gun (torch) when welding aluminium with CO2 process.

Another trick welding aluminium is to remove all oxidation on the alu where you want to weld with sandpaper or file before welding it.

From experience I have found that it is easier to push the weld rather than pulling it as an arc weld. Because of the torch nozzle size, it is easier to see where you are welding and it produce a better looking weld.
Beware of wind that may blow the gas away and causes porosity in the weld. Check the flow or regulator gauge that you have enough shielding gas on the weld.

I hope this will help you in a way my friend.

Wynand

 

[captain butch]

Thank's for those tips. I havn't bought the Lincoln welder yet but I will check the OCV as you suggest. I have held off on this particular welder because I am still unsure of it's ability to handle the stock I generally use.

Butch

 

[Thunderhead19]

nitpicking

Another trick welding aluminium is to remove all oxidation on the alu where you want to weld with sandpaper or file before welding it.
Wynand

Well..technically, it is impossible to remove all the oxidation on the aluminum as it replaces itself in microseconds. You can remove the closed-pore oxidation (old and foggy), and it would be replaced by an open-pore oxide layer (new and shiny).

Sorry, I learned that a month ago from a metalurgist and have been dying to share...

 

[8knots]

One of my Sign guy customers just bought the Lincoln your talking about getting. works fine on 1/8" but struggles with 3/16" its just not hot enough to get full penetration on the heavier stuff. you can and should bevel your heavy stuff and maybe do a multi pass if your not doing lots of 3/16" or
better.

Aluminum is tough to do cheaply...in any kind of volume that is. you can do it with the smaller machines out there just weigh the dollars to the fiddle/cuss factor.
Thats all I have.....Good luck! 8

 

[captain butch]

8knots; What you say about fiddle and fuss is really true. The problem I face is going from a 175 to at least a 200. The cost factor is so great that I really can't justify it. The next unit up that I looked at was well over $1000. If I were commercial I wound not hesitate but as a hobbyist I think my wife might think about murder. By the way I used to live in Alaska, are you familiar with Lime village? I lived in Sparravon about 30 miles South of Lime.

Butch

 

[Arrowmarine]

Just to add to thunderheads post, todays good machines have "self cleaning arcs"" meaning they remove the oxidation as you weld. How this is actually accomplished I couldnt tell ya. ( check the Miller site) But as stated, no matter how clean you get the metal, it is still oxidized. Now, what will hurt your weld is oil, dirt, the white residue that is left during oxidation, etc. etc. Be sure to clean all foriegn substances with a wire brush or solvent.

Next point, As much as I would like to tell you that there is a good dependable welding machine that will easily handle 1/4" to 3/8" aluminum for under $1000 out there, well.......... I've never used one. My home machine is a millermatic 250 w/ 30a spool gun and it would be my recommendation to the "serious" hobbyist welder. Unfortunately, thats gonna cost you $3000 or better. The miller matic 210 is a good machine, but I feel it comes up a little short on 3/8" or better aluminum. (Incidently, the 250 welds steel like a dream as well)
A wire feeder is not necessary for you. Look towards a spool gun. Buying 1 lb. spools at about 5 bucks apiece is much easier, for men like us on a budget, than spending 80 or 90 bucks for a 16 lb. spool. I have used the miller XRa feeders extensively as well as the cobramatic and I prefer them for production work. (More postive feed and less wire changes). But a properly set up spool gun will run every bit as good as any feeder. Dont believe me? Bring me your gun
The miller 185 comes with its own special little gun that works with IT and IT only. At least it used to be that way. Its kind of an underpowered little unit and the gun has a lot to be desired, but for your purposes it would probably work just fine. Around $1800 new My best suggestion is find a good used miller or lincoln. The spool gun is the killer. Mine was $900 new ouch! But they are out there. My buddy picked up a miller 300 w/ spool gun for 75 bucks. Didnt work. Replaced the main fuse. Guess what? Still going strong today after about 5 yrs.
Lets see what else......... Oh, dont waste your time with co2. Run straight argon for good consistant weld quality. Helium is slightly cleaner, but more expensive and not really worth it. (You're not building the next shuttle, right?) I have never had a problem with argon and a quick conservative estimate puts me at around 25,000 hours behind the triggers of aluminum mig welders.
Now, DONT GET YOUR HOPES UP!! but I have a whole pile of older CK spool guns that I have to pick thru along with some weld control units. Hell, I'll give em to you if I find a good set. All you would need is a good used powerhead of at least 180 or 200 v. Like I said its a crap shoot, but if you are interested email me for more details.

Good luck, Joey
I

 

[captain butch]

Joey; thanks for the info. I have been looking for a good used unit but haven't found anything. I appreciate the offer of the spool guns but I had better hold off until I settle on something for a powerhead. If you don't mind I'll contact you when I get something.

Butch

 

[Alan Gluyas]

For what it is worth, I will throw in my opinion here as well. I have built several steel and wooden vessels over the last 20 years but designed and built my first alloy (28 feet) boat two years ago. I bought the heaviest single phase (240 volt) machine available, which was a 260 amp machine with push feed on a 10 foot stinger. The suppliers all looked very doubtfull that this was a big enough machine for what I wanted, but I did not want to go for a 440 volt three pahse machine, as this would limit its resale value.

The 260 amp machine was big enough, but on a couple of the heavier welds I had it on maximum settings. This was when welding 5mm plate to 10mm flat bar for the chine weld and 28mm round bar to 5mm plate on the stem.

I would not use anything apart from argon for shielding gas. Helium mixtures are better for high penetration in thicker material and being lighter are also better for overhead welding. Helium is much dearer and you use more of it when welding downhand.

It sounds as though some of the people writing in this thread are learning alloy welding as they go. I would not recommend this. A course in MIG welding will pay for itself. Because MIG is a semi-automatic process, machine settings and weld procedures are critical. If you make a bad weld in alloy, you will not know until it fails, which could be catastrophic. In a MIG welding course, you are taught what causes a wedl to be rejected for visual faults and whwn you are making welds that pass visual inspection you are taught how to cut the weld test piece up and acid etch it to see just how good it is inside. Then you break it and see how strong it is. If this worlks, you note down all the machine settings in a procedure and use then settings next time you make this kind of weld.

If you are making MIG welds without this sort of testing you are risking wasting a large quantity of expensive alloy. With MIG welding you cannot vary speed, angle, etc as you go. The settings must be right. You also cannot weld backwards. If you do not "push" the gun, you are not getting the benefit of the shielding gas where you need it.

Cleaning the alloy is essential. It should be degreased and sanded clean of all old mill scale before assembly and it should also be wire brushed with a clean stainless steel wire brush immediately before welding. The oxide on alloy melts at a much higher termperature than the metal and if you do not get rid of it it will sit in the weld in flakes and weaken the weld. With new plate material you can get away with just the wire brush but with weathered plate and all extrusions you have to sand or grind the mill scale off. If you don't, the weld will sit on the parent material like bird droppings and fall off.

Welding with a "push" feed gun was a pain at times, but with an overhead gantry to hold the wire feed unit, it was adequate for my boat (see picture). The spool gun might be OK, but if I had used one, I would have to build the boat differently, beacuse I don't think I could have got the bulkier unit into all the places I did.

Cheers and good luck.

 

[captain butch]

Thanks for that; I am going to take a MIG course in the next semester. The local college offers a two semester course that allows certification at the end. I only hope I can get to the point all of you gentlemen are now at. Though my goals are much more modest and my welding will be mainly in fabrication on trailers and other gear. Just a note that the Lincoln 175 turns out to be a lower end model built for the mass market and the price jumped to $617 so I bought a new Hobart Handler 180 from Airgas. They had the best prices around, about $100 bucks less than the "discount" places. I may still need a spoolgun, I'll have to wait and see.

 

[Arrowmarine]

I only have one thing to say to Alan:
That is really a great looking boat! Fantastic lines. Great job. Is that your own design? Do you have any more pics?
Joey

 

[Alan Gluyas]

Yes, I designed it specifically to give good performance between 5 and 15 knots, as I have a place on a river area where there is a lot of concern about wake damage. This boat leaves no wash at all at 5 knots, which is the regulated speed for the river/canal area, and virtually no wash up to 7 knots. It does this with a 70 HP Nissan inboard diesel. Top speed empty has been around 15 knots and she cruises very comfortably in any sea conditions at 13 to 14 knots at about 10 to 12 litres per hour consumption.

I have just towed the boat 500 miles north to a place called Shark Bay and it towed very well at 50 to 60 mph. We spent a week living on board, fishing and diving ( it is sub tropical up there ). We are very pleased with the boat. Most boats in Western Australia are designed to go 40 miles offshore and come back the same day. There are very few trailerable cruising boats available.

I based the design loosely on the US east Coast "double wedge" hull shape that seems to be seeing a resurgence in the current "lobster yacht" style.

This hull form is very fine forward which gives a very smooth ride and flat aft. It is not very efficient above 20 knots, as it causes a lot of turbulence as the water tries to follow the twist or warp in the hull. It does not go through a "hump" as it goes onto the plane, and some experts would argue that at 15 knots this boat is not planing at all, being long and skinny (28 feet by 8 feet).

It is not perfect, as the broad quarters are inclined to lift in a following sea and some active steering input is required in long seas. The mark 2 version that I am just finishing the desig for, will hopefully fix this problem. watch this space!

Cheers and thanks for compliment. I hope you like the photos, I have plenty more!

 

[Arrowmarine]

Thanks, It's beautiful. Seems like we see way too few really nice looking aluminum boats. Although this style is not my forte, I know what it takes in the design, developing, and construction aspects, to get a finished aluminum boat to look this nice. Great proportions. I would like to see the inside as well, if possible.

Peace, Joey

 

[captain butch]

Joey, while your visiting this thread, I wonder if you think the Hobard 180 will do the job as far as 3/16 to occasional 1/4 aluminum? Also will it need a spoolgun to do it?

Butch

 

[8knots]

10 Pionts

Well Done Alan!
8